Revoluble drying drum



Feb. 17, 1931.- A; S CHWIETER REVOLUBLE DRYING mum Filed June 6. 1929 1 I I .7 mm 7 m J H a m M RM M i W i H r :7 A, n v 5 r m F I. V e m 2: a U m-w I .9 Wm m .u N v m w Patented Feb. 17, 1931 UNITED STATES PATENT OFFICE ARTHUR SOHWIETER, OI MEISSEN, GERMANY, ASSIGNOR TO THE FIRM MASCEINEN-- IQLBBIK IMPERIAL G. M. B. 3., OF MEISSEN', GERMANY mowers name mum This invention relates to a revoluble drying drumv in which the material to be dried is passed between a perforated heating drum and an outer drum while the heating gases flow in through an internal distributing pipe.

The object of the invention in its broad aspect is to provide a device of the said kind adaptedto effect positive drying in a drum of rather small length.

A more specific object of the invention is to provide a device in which materials are dried by the heating medium both the materials and the medium travelling partly in the same direction partly in counter current relation to the said medium.

Another object of the invention is to provide between the two ends of the drying device a discharge opening for drawing ofi' the heat- I ing (gases, the said gases being admitted into the evice from the aforesaid two ends of the same.

A still further object of the invention is to provide around the discharge ranged between the two ends of e device a chamber for drawing oif the heating gases from the said discharge opening.

Heretofore in drums of the above-mentioned kind the heating gases have been I drawn oif at the point, where the material leaves the drum. This, however, has sometimesled to disadvantages, as, under these circumstances, the completely dried material comes into contact with the heating gases which are saturated with moisture.

According to the present invention these disadvantages are avoided by first sub'ecting' the material to be dried to acurrent owing in the same direction as that in which said material travels the material substantially 40 tre -yelling throughout the whole length of the drum from one end to the other and. then, after the material has reached a certain degree of dryness, subjecting it to a current flowing in the opposite direction to which it travels until the end of its journey is reached.

zpening arexam le of a drying drum of the kind as 868,954, and in Germany e, 1, 1927.-

This is attained by providing the outer drum, at a certain portion of the shell thereof, with perforations through which the heating ases are drawn ofi into a stationary heating 0 amber. which surrounds the drum at this point. The position of these perforations depends upon the nature of the material to be dried and the degreeof drying desired. In order to provide such perforations the construction of the outer drum may be such that the shell is.

-part iall or wholly omitted, the outer shell being ormed, as it were, of two drums arranged at a certain distance apart and co-- axially. For connecting the several drums together it is convenient to utilize the angle irons provided for the attachment of the outer blades, which angle irons are attached to the inside of the shells of the two separate drums. In certain cases it may be convenient to provide sieve portions in the shell of the outer drum to'permit of the passage of the drying gases,

With these and other objects in mind, I have shown my invention on a constructional mentloned above, the said constructional exam 1e being shown in the accompanying drawing, in which,

Figure 1 is a longitudinal section of the central portion of the drum and.

- Figure 2 is a cross section on the line II-II of Flgure 1 while,

Figure 3 is a cross section on the line III-III of Figure 1.

Referring now to the drawings 1 is a heating drum, which is rovide'd in the usual manner with inclined lades 2 secured thereto.. The said heating drum 1 is surrounded by and secured to by staybolts 18 to an outer drum 3 to which are secured in any suitable manner and corresponding to the aforesaid blades 2 further blades 4, 4 for the conveyance of the niaterial to be dried.

The heating gases are supplied through an the heating drum 1 and connected thereto by I outer drum 3 is interrupted at 8 (Fig. 1),

thus dividing the said drum into two portions 3 and 3", which are connected to one another by the angles 9, 9' of the blades 4, the said angles extending throughout the whole length of the drum 1. The heating gases are permitted to pass freely through the intervals left by the said blades 4 within the space 8 arranged between the two ortions 3 and 3 of the outer drum 3. assing through the space 8 the gases reach the chamber 10, whence they are drawn off by means of a fan 11 or the like. As is shown in Figs. 2 and 3 of the drawings, the chamber 10 is of rectangular cross-section, the said cross section embracing the cross section of the outer drum 3; the chamber 10 may be built up from sheet'metal, the single walls or parts of walls being connected to one another by means of channels 12 or angles 13 riveted or bolted to the said walls or secured thereto in any suitable manner. On the top the chamber 10 may be extended by an annex 10', the latter containing the said fan 11. The annex 10 too may be built up from sheet metal, the single plates of which may be connected to each other and to the walls of the lower main portion of the chamber 10, by means of channels or angles secured to the sheet metal in any suitable manner on the sides ofthe annex 10 of the chamber 10 there are provided on the cover plate 13 of the latter bearings 14, 14, in which the shaft 15 of the fan 11 is journalled. The fan 11 is operated by means of a pulley 16 provided on one end of the said shaft 15.

The direction in which the heating gases flow is indicated in the figures by arrows. If it be assumed that the material to be dried travels from the left'to right,it will, on the side lying to the left of the open s ace 8 of the drum be heated by a current owing in the direction in which said material travels and thereby to intensive preliminary drying. When the material reaches the open space 8 it falls through the intervals left between the blades 4 extendin over the said space on to the trough-shape floor 17 of the chamber 10. As there is only a small amount of space between thefioor and-the intermediate portions of the above-mentioned blades 4, which sweep past, the material which piles up in front of the said blades, will be raised from the said floor 17, and, owing to the inclined position of the blades, moved onwards a certaln portion of the material always remaining behind. If sieve members not shown he provided between the portions 3' and 3" of the outer drum 3 the material to be dried travels uninterruptedly from one end of the drum to the other. When the material has passed out behind the part 8 the heatin gases act in the opposite direction perfect rying being thus obtained. This arrangement also enables the gases to flow at a lower velocity and by a shorter path than is otherwise possible without the gases in so doing being less efiiciently utilize 1 While I have shown only one form of embodiment of my invention for the purpose of describing the same and illustrating its principles of construction and operation, it is apparent that various changes and modifications may be made therein, without departing from the spirit of my invention. I desire, therefore, that only such limitations shall be imposed thereon, as are indicated in the appended claims and as are demanded by the prior art.

I claim:

1. A rotary drier having an outer drum and an inner perforated heating drum rotatable together, means for feeding the material between said drums from one end to the other end thereof, means for supplying heating gas to the inner drum, a casing surrounding a part of the length of the outer drum, said part having passages for the gas and means for exhausting said gas through said casing whereby heating gas and material travel parallel in one portion of the drier and counterwise in the other part.

2. A rotary drier having an outer drum and an inner perforated heating drum rotatable together, means for feeding the material between said drums from one end to the other end of said drums, a heating pipe having passages opening within said inner heating drum and extending from one end to the other end of said drier for supplying heating gas to theinner heating drum, acaslngsurrounding a part of the length of the outer drum, said part having passages for the gas and means for exhausting said gas through said casing whereby heating gas and material travel parallel in one portion of the drier and counterwise in the other part.

3. A rotary drier as in claim 1 wherein the outer drum comprises two spaced parts terminating into said casing and wherein angle rails are provided on the inner side of the outer drum on the whole length of the same, to connect both drum-parts, said rails carrying blades for feeding the material.

4. A rotary drier, comprising an outer drum composed of two longitudinally spaced sections connected together into which the material to be dried is charged; a perforated heating drumwithin the outer drum and a centralperforated p ipe within the heating .drum, all connected together to rotate as a 

